Non-tuberculous mycobacteria: five year experience

Introduction: Non-tuberculous mycobacterial (NTM) infections are increasingly rapidly worldwide. NTM differ in their pathogenicity with propensity to cause disease in patients with impaired immunity. Objective: To characterize the population with NTM isolation in our centre over a 5-year period. Methods: Retrospective analysis of patients with at least one NTM culture isolation between january of 2014 and december of 2018. Demographic, clinical, radiological, and microbiological data were collected. Statistical analysis was performed using SPSS. Results: Ninety patients were included, of which 67,8% were male, and had a median age of 69 years. Most patients were non-smokers (58,8%); 45% were farmers or bricklayers/miners. The main risk factors were underlying structural lung diseases such as bronchiectasis (n=23), COPD (n=8), tuberculosis sequelae (n=7), silicosis (n=6) or other diffuse lung disease (n=6), lung cancer (n=6), alpha-1-antitrypsin deficiency (n=1). Non-pulmonary predisposing conditions include alcohol abuse (23%), diabetes (17%), gastroesophageal reflux disease (16%) and immunossupressive conditions/drugs (16%). Mycobacterium avium complex (MAC) and M.intracellulare was the most commonly isolated NTM (46,5%), followed by M.lentiflavum (19%). Isolates were obtained from bronchial lavage fluid and/or bronchoalveolar lavage samples in 53% of cases. Nodular bronchiectatic radiological pattern predominated (56,6%). 37,8% patients underwent treatment for NTM-related lung disease. Conclusions: Our results confirme the role of increased prevalence of chronic lung disease and immunosuppressive conditions in the pathogenesis of NTM infection. According with literature, MAC account for the majority of NTM isolated in our hospital.